Time pieces without hands, which indicated the time with moving or jumping numbers on rotating disks or rings, appeared as early as the 16th century. However, these were monumental clocks on towers or churches.
In the second half of the 19th century, jump hour pocket watches appeared, which digitally indicated both the hours and the minutes through mechanically jumping digits, wherein the seconds, however, were indicated in analog with a hand. In particular, the manufacturers IWC, Cortébert Watch, Gedeon Thommen, Aeby & Landry, Kaiser, and others produced such jump hour pocket watches. The expert can find an overview of this production at that time in the book “Die Sprungziffern-Taschenuhren” by Alex Kuhn, publishing company Simonin, 2010. The first technical descriptions of this type of watch can be found in particular in the so-called Pallweber patents, see, for example, the German Reich Patent 25 042 from 1883.
In the meantime, these pocket watches have been essentially completely ousted from the market by mechanical wristwatches with analog displays. In the sixties, cheaper electronic wristwatches with digital displays of any kind also appeared, which, at first glance, made a further development of mechanical watches with digital display seem little meaningful. In view of the current demands of the consumer in terms of accuracy of indication and adjustability, the field of mechanical watches having a digital time display can thus again be regarded as technical new ground.
A few innovations with respect to the pocket watch production of the 19th century shall be mentioned in the following:
The patent specification DE 10 2007 042 797 discloses a watch, in particular a wristwatch, having a main energy storage, by which, via a gear train, a tensioning element of a tensioning device forming a first device configured to be switched in a stepwise manner can be rotatably driven, controlled by a tensioning control, in cyclic steps about a tensioning axis and a storage hairspring connected with one end to the tensioning element is tensioned, wherein the other end of the storage harspring is connected to a wheel rotatably driving the movement, which is engaged with the train of the escapement, wherein a further device configured to be switched in a stepwise manner can be rotatably driven in cyclic steps by an element of the gear train from the main energy storage to the tensioning element. The movement of this watch is mainly used in so-called movements with constant torque and therefore has a tensioning device charging the storage hairspring at regular time intervals to avoid large torque fluctuations.
The patent specification DE 10 2009 019 335 discloses a watch, in particular a wristwatch, having a drive, through which a gear train of a digital display having a plurality of numeric disks can be rotatably driven in cyclic steps, wherein a drive wheel allows to rotatably advance a units wheel of a minute-units disk with ten steps per revolution, with a switching device which is driven by the units wheel and which allows to rotatably advance a minute-tens disk with six steps per revolution, and with an numeric hour disk which can be advanced rotatably by the minute-tens disk with twelve steps per revolution during a revolution of the minute-tens disk, wherein a pinion which engages in the gear train can be driven by a manually actuatable disk adjusting wheel, wherein the pinion is positively coupled via a locking mechanism with the drive wheel. The coupling realized by said locking mechanism between the pinion manually drivable by the disk adjusting wheel and the drive wheel of the train of this watch has a specific configuration and, in particular, is mounted axially sliding on the axis of the pinion arranged coaxially with the drive wheel, wherein the train is designed as a continuous gear train with successively driven numeric disks in order to save installation space and to reduce the number of components.
Swiss patent specification CH 511 471 also discloses such a watch, wherein a minute-units disk may be advanced rotatably with ten steps per revolution, with a switching device by which a minute-tens disk may be advanced rotatably with six steps per revolution and with an numeric hour disk which may be advanced rotatably by the minute-tens disk with twelve steps per revolution during a revolution of the minute-tens disk. The movement has a first transmission chain which transfers the force from a first barrel to a first escapement of a regulator of the watch, and a second transmission chain which transmits the force from a second barrel to the indicator disks, wherein the rotation of the wheels of the second transmission chain is controlled by a wheel of the first transmission chain. The necessary blocking of the second transmission chain between the stepwise advancing of the indicator disks as well as their release at the time of a step of advance is accomplished via second pallets of a second escapement in cooperation with superimposed, mutually rotatable plates, which requires a relatively complex structure of the movement.
An instantaneous display mechanism of a watch of this type is disclosed in the Swiss patent specification CH 581 857, wherein a drive wheel of a indicator disk meshes with an intermediate wheel, which is mounted on a rocker. A block of the rocker is engaged with a toothing of the disk, however, the block is released from the toothing both during a manual correction operation as well as by the automatic dislocation of the rocker during the normal course of the watch.
The European Patent Application EP 3 032 348 also discloses an instantaneous display mechanism which comprises a drive wheel, a time display and a jumping member that is mounted on said time display and coaxial with the drive wheel, as well as a cam configured to release four-arm pallets once per unit of time. This arrangement is especially designed for displays that realize a jumping switching every second, in particular using a single source of energy in the watch movement.